A few thoughts about beacons to consider if you decide to implement them:

...

These are great thoughts--thank you!

The easiest way to implement beacons is to check for them only at the time that a destination is set. If the destination is in range of a (friendly) beacon, then it works; otherwise, the player gets an error message. It doesn't matter where the jumpfleet is currently--only where it's trying to go. Thus, we can answer your questions:

Mixed fleets: Jumpships + starships move at starship speed as always. They have no restrictions on destinations. If you have a mixed fleet outside of beacon range and deploy jumpships, the jumpship fleet can only be targeted to points inside beacon range (but it moves at jump speed, even through non-beacon territory). NOTE: Explorers are exempt from needing beacons, so we also have to deal with mixed jumpships + explorer fleets (which move as jumpships do).

Captured beacons: If a jumpship is in transit to some point inside a beacon range and the beacon is captured, the jumpship still moves. It can be re-targeted at any time, but only to points inside beacon range. If there are no beacons left, the jumpships cannot move (but the capital is probably always a jump beacon).

Passing through non-beacon space: In this proposal, yes, jumpships have no problem passing through non-beacon space. They don't even need a beacon at the origin point--only the destination (and only when the destination is set).

Beacon activation time: I think it is OK, for a first pass, if jumpship beacons are immediately activated, as soon as a world is designated. This feature is meant to minimize surprise attacks on a distant empire. But once you've conquered a world with slow ships, then jumpships can come in. If this ends up being too overpowered, we can implement activation times.

Beacon details: I think in the first version beacons are just intrinsic to certain designations. Capitals, jumpship yards, sector capitals for the Fire & Movement doctrine, and maybe citadels. The range should probably be fixed at 250 light-years (same as administrative range) but we can change this later as needed. If we allow other designations to get beacons, then I think they should consume labor. [In practice, though, I'm not sure this will be necessary.]

Beacon construction: At some point we'll be able to build space stations in deep space; those will have designations just like planets (though a different set of them). I can imagine one designation will be the equivalent of a jumpship base, which again would come with a beacon. Perhaps there could be stand-alone beacon constructions too--not sure. In either case, they would behave very much like worlds (though with smaller populations) and would get defenses, industry, etc.

Warp transports: Yes, we need to introduce warp transports. Technically, you can use jumptransports in a warp fleet, so I don't think there is pressing need, but we will introduce warp transports. Not sure if they will be built by regular starship yards or if they require a new designation.

Let me know what you all think of this proposal. I think I can at least implement the core concept of beacons in this beta. Other things like constructions and warp transports would wait until a future beta.

I think this is a pretty good feature set. If jumpships are able to convoy with starships, this does eliminate a pressing need for warptransports.

It sounds like jumpships don't have an intrinsic ability to move at slower speeds beyond beacon range, but will do so if convoyed with slower ships. The game will need to handle the situation where a mixed fleet moving at gunship/starship speed gets hit with jumpmissiles and has the starships/ramjets destroyed, or if the starships in a mixed fleet are lost to attrition during transit but jumpships remain.

The most intuitive course of action (to me) would be to have it continue to its destination at slower speed by default, but then become a normal jumpfleet on arrival. If a mixed fleet becomes a jumpfleet in transit it should be possible to order it to a new destination that's within beacon range and have it start moving at jumpship speed. Otherwise, it would be possible to reassign it to a new destination and have it continue on at gunship/starship speed, which doesn't seem right.

...
The game will need to handle the situation where a mixed fleet moving at gunship/starship speed gets hit with jumpmissiles and has the starships/ramjets destroyed, or if the starships in a mixed fleet are lost to attrition during transit but jumpships remain.
...

Good point! I had not considered this. If you hadn't said anything, the jumpships would have continued to their destination AT JUMP SPEED, which would have opened up a serious exploit.

I think it's reasonable to implement your idea: the jumpships continue at warp speed. Alternatively, the jumpships can halt and the player will be forced to set a new destination (which, of course, will have to be within beacon range).

The latter might be my first attempt, considering the situation should be relatively rare.

There are no other circumstances under which a fleet can halt in open space without ongoing player input. This opens up another exploitable situation- namely, that a halted fleet is invulnerable to conventional attack.

In keeping with the idea of beacons, citidels could be used as disrupters so enemy jumpships move at starship speeds. Citidels could nullify enemy beacons.

I understand that it could be difficult to introduce a whole new mechanic like building in open space, but you could use planets instead.

Consider this......

An enemy designates a planet on the edge of your territory as a beacon so that jumpships can operate around it. (Or starship fleets above a certain size can operate as beacons). However, even with the beacon, enemy jumpships can't jump within range of your citidel, but your own jumpships can. This would solve several issues with the game.

1. Wars would be slowed down giving players time to react, since you would use citidels around your sector capitals and the enemy can only approach at starship speed.

2. It would allow for more strategey, cititdels would become hardpoints, and you would use them to form a border.It

3. It would make offence harder then defence. If a citidel acted as both beacon for your forces, and disrupter for enemy forces, then you would have several opportunitys to attack an enemy fleet appoaching your citidel. An attacker would have to come in with overwhelming force, and you would have time to prepare.

In keeping with the idea of beacons, citidels could be used as disrupters so enemy jumpships move at starship speeds. Citidels could nullify enemy beacons.
...

I like this idea! This is a little hard to implement, so I'm not going to do it this week, but it makes sense.

I'm not sure if all citadels should get this by default or if you need a special structure or a special citadel type. For example, maybe the Strength & Honor doctrine gets a special citadel type that acts as a disruptor. Or maybe there is an upgrade to a standard citadel that yields this.

There are no other circumstances under which a fleet can halt in open space without ongoing player input. This opens up another exploitable situation- namely, that a halted fleet is invulnerable to conventional attack.

You're right, but I'm not sure it gives you much of an advantage. In any case, we will eventually have to support fleets in open space (to support constructions) and we'll want to allow fleets to intercept other fleets in open space.

Also, this is a specific case of a general situation in which a fleet transforms while in transit. There are two transform cases:

1. A fleet that requires jump beacons transforms to one with unrestricted destinations. In this case we don't need to do anything. The fleet should continue to the destination at its normal speed.

2. A fleet with unrestricted destinations transforms to a jumpfleet. In that case, we can't continue to the original (unrestricted) destination at jump-speeds or else we open up an exploit. But imagine a case where an explorer fleet (unrestricted destination) transforms to a jumpfleet (via a transfer). In that case, we can't continue to the destination at jump-speeds. But does that mean that we artificially lower the speed to warp speed even though there are no warp ships involved? Better to halt the fleet all together, I think.